This is a Divisional application of
U.S. patent application Ser. No. 08/235,814, filed Apr. 28,
1994; which is a Continuation-in-part of 07/958,196, filed
Oct. 7, 1992 abandoned; which is a Divisional of Ser. No.
07/629,809, filed Dec. 19, 1990, now U.S. Pat. No.
5,278,316; which is a Continuation-in-part of Ser. No.
07/545,222, filed Jun. 28, 1990, abandoned; which is a
Continuation-in-part of Ser. No. 07/530,811, filed Jun. 5,
1990, abandoned; which is a Continuation-in-part of Ser. No.
07/422,486, filed Oct. 16, 1989, abandoned; which is a
Continuation-in-part of Ser. No. 07/374,327, filed Jun. 29,
1989, now abandoned.

Claims:

We claim:

1. A method of treating pain in a mammal, comprising administering an effective amount of a compound of formula ##STR166## or a pharmaceutically acceptable salt thereof wherein: R1 is a cycloalkyl or polycycloalkyl hydrocarbon of from three to twelve carbon atoms with from zero to four substituents each independently selected from the group consisting of a straight or branched alkyl of from one to about six carbon atoms, halogen, CN, OR*, SR*, CO2 R* , CF3, NR5 R6, and --(CH2)n OR5 wherein R* is hydrogen or a straight or branched alkyl of from one to six carbon atoms, R5 and R6 are each independently hydrogen or alkyl of from one to about six carbon atoms and n is an integer from zero to six;

A is --(CH2)n CO--, --SO2 --, --S(O)--, --NHCO--, ##STR167## --SCO--, --O--(CH2)n CO-- or --HCCHCO-- wherein n is an integer from zero to six;

R2 is a straight or branched alkyl of from one to about six carbon atoms, --HCCH2, --C.tbd.CH, --CH2 --CHCH2, --CH2 C.tbd.CH, --(CH2)n Ar, --(CH2)n OR*, --(CH2)n OAr, --(CH2)n CO2 R, or --(CH2)n NR5 R6 wherein n, R*, R5 and R6 are as defined above and Ar is as defined below;

R3 and R4 are each independently selected from hydrogen, R2 and --(CH2)n' --B--D wherein:

n' is an integer of from zero to three;

B is a bond, ##STR168## wherein R7 and R8 are independently selected from hydrogen and R2 or together form a ring (CH2)m wherein m is an integer of from 1 to 5 and n is as defined above; ##STR169## S is in integer of from 0 to 2; wherein R*, R2, R5, and R6 are as defined above;

R9 is hydrogen or a straight or branched alkyl of from one to about six carbon atoms, --(CH2)n CO2 R*, --(CH2)n OAr', --(CH2)n Ar' or (CH2)n NR5 R6, wherein n, R*, R5, and R6 are as defined above or taken from R3 and Ar' is taken from Ar as defined below;

R12 and R13 are each independently hydrogen or are each independently taken with R3 and R4 respectively to form a moiety doubly bonded to the carbon atom; and

Reduced levels of CCK-peptides have been found in the brains of schizophrenic patients compared with controls (Roberts, Ferrier, Lee, Crow, Johnstone, Owens, Bacarese-Hamilton, McGregor, O'Shaughnessey, Polak and Bloom. Brain Research 288, 199-211, 1983). It has been proposed that changes in the activity of CCK neurones projecting to the nucleus accumbens may play a role in schizophrenic processes by influencing dopaminergic function (Totterdell and Smith, Neuroscience 19, 181-192, 1986). This is consistent with numerous reports that CCK peptides modulate dopaminergic function in the basal ganglia and particularly the nucleus accumbens (Weiss, Tanzer, and Ettenberg, Pharmacology, Biochemistry and Behaviour 30, 309-317, 1988; Schneider, Allpert and Iversen, Peptides 4, 749-753, 1983). It may therefore be expected that agents modifying CCK receptor activity may have therapeutic value in conditions associated with disturbed function of central dopaminergic function such as schizophrenia and Parkinson's disease.

CCK and gastrin peptides share a common carboxy terminal pentapeptide sequence and CCK peptides can bind to the gastrin receptor of the stomach mucosa and elicit acid secretion in many species including human (Konturek, Gastrointestinal Hormones, Ch. 23, pp 529-564, 1980, ed. G. B. J. Glass, Raven Press, New York). Antagonists of the CCK-B receptor would also be expected to be antagonists at the stomach gastrin receptor and this would also be of value for conditions involving excessive acid secretion.

CCK and gastrin peptides have trophic effects on the pancreas and various tissues of the gastrointestinal tract (Johnson, ibid., pp 507-527), actions which are associated with increased DNA and RNA synthesis. Moreover, gastrin secreting cells are associated with certain gastrointestinal tumors as in the Zollinger-Ellison syndrome (Stadil, ibid., pp 279-739), and some colorectal tumors may also be gastrin/CCK dependent (Singh, Walker, Townsend and Thompson, Cancer Research, 46, 1612 (1986), and Smith, J. P., Gastroenterology, 95 1541 (1988)). Antagonists of CCK/gastrin receptors could therefore be of therapeutic value as antitumor agents.

The CCK peptides are widely distributed in various organs of the body including the gastrointestinal tract, endocrine glands, and the nerves of the peripheral and central nervous systems. Various biologically active forms have been identified including a 33-amino acid hormone and various carboxyl-terminus fragments of this peptide (e.g., the octapeptide CCK26-33 and the tetrapeptide CCK30-33). (G. J. Dockray, Br. Med. Bull., 38 (No. 3):253-258, 1982).

The high concentrations of CCK peptides in many brain areas also indicate major brain functions for these peptides (G. J. Dockray, Br. Med. Bull., 38 (No. 3):253-258, 1982). The most abundant form of brain CCK found is CCK26-33, although small quantities of CCK30-33 exist (Rehfeld and Gotterman, J. Neurochem., 32:1339-1341, 1979). The role of central nervous system CCK is not known with certainty, but it has been implicated in the control of feeding (Della-Fera and Baile, Science 206:471-473, 1979).

Currently available appetite suppressant drugs either act peripherally, by increasing energy expenditure (such as thyroxine), or in some other manner (such as the biguanides), or act by exerting a central effect on appetite or satiety.

The invention relates to novel compounds of the formula ##STR1## and the pharmaceutically acceptable salts thereof wherein R1, R2, R3, R4, R9, R12, R13, A and Ar are as defined hereinbelow.

The invention also relates to a pharmaceutical composition containing an effective amount of a compound according to formula I in combination with a pharmaceutically acceptable carrier in unit dosage form effective for appetite suppression.

The compounds are also useful as anxiolytics, antipsychotics, especially for treating schizophrenic behavior, as agents in treating disorders of the extrapyramidal motor system, as agents for blocking the trophic and growth stimulating actions of CCK and gastrin, and as agents for treating gastrointestinal motility.

Compounds of the invention are also useful as analgesics and potentiate the effect of morphine. They can be used as an adjunct to morphine and other opioids in the treatment of severe pain such as cancer pain and reduce the dose of morphine in treatment of pain where morphine is contraindicated.

The compounds of the instant invention are also useful as antidepressants. The invention further relates to a pharmaceutical composition for treating depression containing a therapeutically effective amount of a compound of formula I in combination with a pharmaceutically acceptable carrier in unit dosage form for treating depression.

The invention also relates to a method for treating and/or preventing depression in mammals which comprises administering an effective amount of the composition described above to a mammal in need of such treatment.

An additional use for compounds such as the iodinated compound of Example 26 is that the suitable radiolabelled iodine-127 isotope gives an agent suitable for treatment of gastrin dependent tumors such as those found in colonic cancers. I-125 radiolabelled compound of Example 26 can also be used as a diagnostic agent by localization of gastrin and CCK-B receptors in both peripheral and central tissue.

The invention further relates to a method of appetite suppression in mammals which comprises administering an amount effective to suppress appetite of the composition described above to a mammal in need of such treatment.

The invention also relates to a pharmaceutical composition for reducing gastric acid secretion containing an effective amount of a compound of formula I in combination with a pharmaceutically acceptable carrier in unit dosage form effective for reducing gastric acid secretion.

The invention also relates to a method for reducing gastric acid secretion in mammals which comprises administering an amount effective for gastric acid secretion reduction of the composition described above to a mammal in need of such treatment.

The invention also relates to a pharmaceutical composition containing an effective amount of a compound of formula I in combination with a pharmaceutically acceptable carrier in unit dosage form effective for reducing anxiety.

The invention also relates to a method for reducing anxiety in mammals which comprises administering an amount effective for anxiety reduction of the composition described above to a mammal in need of such treatment.

The invention also relates to a pharmaceutical composition containing an effective amount of a compound of formula I in combination with a pharmaceutically acceptable carrier in unit dosage form effective for treating gastrointestinal ulcers.

The invention further relates to a method for treating gastrointestinal ulcers in mammals which comprises administering an amount effective for gastrointestinal ulcer treatment of the composition as described above to a mammal in need of such treatment.

The invention also relates to a pharmaceutical composition containing an effective amount of a compound of formula I in combination with a pharmaceutically acceptable carrier in unit dosage form effective for treating psychosis, i.e., schizophrenia.

The invention further relates to a method for treating psychosis in mammals which comprises administering an amount effective for treating psychoses of a composition as described above to a mammal in need of such treatment.

The invention also relates to pharmaceutical compositions effective for stimulating or blocking CCK or gastrin receptors, for altering the activity of brain neurons, for schizophrenia, for treating disorders of the extrapyramidal motor system, for blocking the trophic and growth stimulating actions of CCK and gastrin, and for treating gastrointestinal motility.

The invention also relates to a pharmaceutical composition for preventing the withdrawal response produced by chronic treatment or abuse of drugs or alcohol.

The invention further relates to a method for treating the withdrawal response produced by withdrawal from chronic treatment or withdrawal from abuse of drugs or alcohol. Such drugs include benzodiazepines, especially diazepam, cocaine, alcohol, nicotine, caffeine, and opioids. Withdrawal symptoms are treated by administration of an effective withdrawal treating amount of a compound of the instant invention; especially useful are compounds (20) and (20A).

The invention further relates to pharmaceutical compositions and to the use of the compounds of Formula I in the treatment of tumor growth, especially in colon cancer.

The invention further relates to the use of the compounds of formula I to prepare pharmaceutical and diagnostic compositions for the treatment and diagnosis of the conditions described above.

The invention further provides processes for the preparation of compounds of formula I.

The invention further provides novel intermediates useful in the preparation of compounds of formula I and also provides processes for the preparation of the intermediates.

The compounds of the present invention are formed by the condensation of two modified amino acids and are therefore not peptides. Rather they are "dipeptoids", synthetic peptide-related compounds differing from natural dipeptides in that the substituent group R2 is not hydrogen.

The compounds of the present invention are represented by the formula ##STR2## or a pharmaceutically acceptable salt thereof wherein: R1 is a cyclo- or polycycloalkyl hydrocarbon of from three to twelve carbon atoms with from zero to four substituents, each independently selected from the group consisting of: a straight or branched alkyl of from one to six carbon atoms, halogen, CN, OR*, SR*, CO2 R*, CF3, NR5 R6, or --(CH2)n OR5, wherein R* is hydrogen, straight or branched alkyl of from one to six carbon atoms, R5 and R6 are each independently hydrogen or alkyl of from one to six carbon atoms; and n is an integer from zero to six;

A is --(CH2)n CO--, --SO2 --, --SO--, --NHCO--, ##STR3## --SCO--, O--(CH2)n CO-- or --HCCHCO-- wherein n is an integer from zero to six;

R3 and R4 are each independently selected from hydrogen, R2, and --(CH2)n' --B--D, wherein

n' is an integer of from zero to three;

B is a bond ##STR4## wherein R7 and R8 are independently selected from hydrogen and R2 or together form a ring (CH2)m wherein m is an integer of from 1 to 5 and n is as defined above; ##STR5## s is an integer of from 0 to 2, wherein R*, R2, R5, and R6 are as defined above;

R9 is H, or a straight or branched alkyl of from one to six carbon atoms, --(CH2)n CO2 R*, (CH2)n OAr', (CH2)n Ar', (CH2)n NR5 R6, wherein n, R*, R5, and R6 are as defined above or taken from R3 and Ar' is taken from Ar as defined below;

R12 and R13 can each be independently hydrogen (in which case the carbon atom to which it is attached is a chiral center) or can each be taken with R3 and R4 respectively to form a moiety doubly bonded to the carbon atom (in which case the carbon atom is not chiral); and

Ar is a mono- or polycyclic unsubstituted or substituted carbo- or heterocyclic aromatic or hydroaromatic moiety.

The indole is numbered ##STR11## for purposes of the above substituents.

Further, the indole can be substituted on the nitrogen by -[(4-methylphenyl)sulfonyl] or by a methyl group.

Preferred cycloalkyl or polycycloalkyl substituents have from six to ten carbon atoms.

Preferred compounds of the instant invention are those wherein cycloalkyl is a substituted or unsubstituted ##STR12## and wherein polycycloalkyl is selected from ##STR13## wherein W, X, Y, and Z are each independently hydrogen, a straight or branched alkyl of from one to six carbon atoms, CF3, NR5 R6, --(CH2)n CO2 R*, or CN, F, Cl, Br, OR*, SR*, wherein R* is hydrogen or a straight or branched alkyl of from one to six carbon atoms and R5 and R6 are as defined above and n is an integer of from 1 to 3.

Tables I and II below illustrate representative compounds of the invention. The numbers on the left hand column correspond to the compound numbers given above. Stereochemistry is not shown in the Table I.

In addition to the compounds of the above tables the compounds of the present invention include compounds of formula I wherein the indole moiety is a 2-indolyl.

The compounds include solvates and hydrates and pharmaceutically acceptable salts of the compounds of formula I.

The compounds of the present invention can have multiple chiral centers including those designated in the above formula I by an .dagger., .dagger-dbl., .dagger-dbl. depending on their structures. For example, when R3 taken with R12 and R4 taken with R13 form double bonds to these carbon atoms they are no longer chiral. In addition, centers of asymmetry may exist on substituents R1, R9, R3, R4 and/or Ar. In particular the compounds of the present invention may exist as diastereomers, mixtures of diastereomers, or as the mixed or the individual optical enantiomers. The present invention contemplates all such forms of the compounds. The mixtures of diastereomers are typically obtained as a result of the reactions described more fully below. Individual diastereomers may be separated from mixtures of the diastereomers by conventional techniques such as column chromatography or repetitive recrystallizations. Individual enantiomers may be separated by convention method well known in the art such as conversion to a salt with an optically active compound, followed by separation by chromatography or recrystallization and reconversion to the nonsalt form.

The preferred stereochemistry of the compounds of the invention is that exhibited by the compound of Example 20.

The compounds of the present invention can be formed by coupling individual substituted α-amino acids by methods well known in the art. (See, for example, standard synthetic methods discussed in the multi-volume treatise "The Peptides, Analysis, Synthesis, Biology," by Gross and Meienhofer, Academic Press, New York.) The individual substituted alpha amino acid starting materials are generally known or, if not known, may be synthesized and, if desired, resolved by methods within the skill of the art. (Synthesis of racemic [DL]-α-methyl tryptophan methyl ester--see Brana, M. F., et al, J. Heterocyclic Chem., 1980, 17:829.)

A key intermediate in the preparation of compounds of formula I is a compound of formula ##STR15## wherein R is selected from R1, 9-fluorenylmethyl, Bz and other suitable N-blocking groups. These are useful as intermediates in the preparation of compounds of formula I. The compounds wherein R is 1-adamantyl, 2-adamantyl, 4-protoadamantyl, exo-bornyl, endo-bornyl, exo-norbornyl, endo-norbornyl, 2-methylcyclohexyl, 2-chlorocyclohexyl, or camphoryl are novel and are preferred.

The disclosure of U.S. Pat. No. 4,757,151 is hereby incorporated by reference. It describes the 9-fluorenylmethyl blocking group.

Compounds of formula II are prepared by reacting ROH III

wherein R is as defined above, with phosgene or a phosgene substitute to produce a corresponding compound of formula ROCOCl IV

and then reacting a compound of formula IV with α-methyltryptophan to produce the desired compound of formula II above.

Alternatively, a compound of formula IV can be reacted with an α-methyltryptophan methyl ester to produce ##STR16## which can be converted to a compound of formula II by known means such as hydrolysis with aqueous lithium hydroxide.

Scheme I below illustrates procedures for preparing intermediates useful in producing final products of formula I.

Key intermediate (2) is prepared from the alcohol form of a radical selected from 1-adamantyl, 2-adamantyl, 4-protoadamantyl, 9-fluorenylmethyl, exo-bornyl, endo-bornyl, exo-norbornyl, endo-norbornyl, 2-methylcyclohexyl, 2-chlorocyclohexyl, and camphoryl. The alcohol is dissolved in a solvent such as methylene chloride. It is then converted to the corresponding chloroformate by reaction with bis(trichloromethyl)carbonate in pyridine at about 0° C. The product is formed by condensation with an amine such as α-methyl-D-tryptophan methyl ester. The reaction is carried out in a solvent such as THF to produce, for example, N-[(2-adamantyloxy)carbonyl]-α-methyl-D-tryptophan methyl ester. This is then treated with lithium hydroxide and stirred at room temperature overnight to produce the corresponding carboxylic acid. This novel key intermediate (2) is useful in the production of compounds of formula I as described hereinafter in Schemes II and III.

Alternatively a chloroformate can be converted to (2) by reaction with an alkaline solution of α-methyl-DL-tryptophan.

In another process, (sequence 3,4,5,6,)tert-butyloxycarbonyl-L-phenylalaninol in pyridine is treated with p-toluene sulphonyl chloride to give the corresponding tosylate. The rosylate is treated with sodium azide in N,N-dimethylformamide to produce the corresponding azide. This is converted to the free aminoazide (6) by reaction with p-toluene sulphonic acid in dichloromethane solution at room temperature. This is then reacted with the desired compound of formula 2 to produce a compound of the instant invention as, for example in schemes I, II and II.

Similarly (sequence 7-12) tert-butyloxycarbonyl-D-2-phenyl glycinol can be converted to the corresponding amine-substituted azide (10) using the above procedure. A solution of benzyl hydrogen succinate is reacted with an equimolar mixture of N,N-dicyclohexyl-carbodiimide and 1-hydroxybenzotriazole. The reaction is carried out in ethyl acetate for about an hour. Subsequent addition of the free amine (10) to the reaction mixture yields an amide (11). The azide portion of (11) is hydrogenated over a Lindlar catalyst to form the amine (12).

A solution of 2-adamantyloxycarbonyl-α-methyl-D-tryptophan in ethyl acetate reacts with an equimolar solution of N,N-dicyclohexyl-carbodiimide and 1-hydroxybenzotriazole. The reaction mixture is left to stir at room temperature for about an hour. Subsequently the amine (12) in scheme I, in ethyl acetate is allowed to react for 18 hours at room temperature to form the dipeptoid benzyl ester (scheme II). Finally, the benzyl ester is hydrogenolyzed for four hours using a palladium on carbon catalyst. After filtering and washing, the filtrate yields the desired product of formula I. ##STR17##

Whenever R in intermediate of formula II is other than R1, it may be removed at an appropriate point in the synthesis by methods known in the art for each respective group and the desired R1 substituted therefore.

Scheme II below illustrates processes for the preparation of compounds of formula I using key intermediate, compound (2) from the Scheme I.

Subsequent addition of 2-amino-1-phenyl ethanol produces an alcohol as in compound (13) of the scheme. This alcohol is then reacted with succinic anhydride to yield compound (14), a compound of the instant invention.

Another process of the invention is illustrated by sequence 2, 16, 15 of Scheme II. In this process intermediate (2) is reacted with DCCI and pentafluorophenol in ethyl acetate. After stirring for an hour at room temperature the mixture is reacted with L-phenylalaninol to yield a compound (16). This is then refluxed with succinic anhydride and DMAP for 24 hours. The reaction mixture is washed and the organic phase dried over MgSO4. Evaporation of the solvent yields a compound as illustrated by (15).

In the sequence 2, 21, 22 intermediate (2) (R is 9-fluorenylmethyl) in solution with pentafluorophenol is treated with a solution of DCCI in ethyl acetate. This solution is stirred for one hour at 0° C. and then for four hours at room temperature. After filtering and washing the precipitated DCU, the combined filtrates react with 2-phenylethylamine to produce compound (21). This compound is converted to the free amine (22) by reaction with a 20% piperidine in DMF solution. This can be treated with a substituted chloroformate to produce the desired amide (21).

In another process, sequence 2, 16, 17, and then 18, or 19 or 20, compound (12) is converted to compound, (16) (R is 9-fluorenylmethyl) as discussed above. The amide (16) is converted to a free amine (17) by reaction with 20% pyridine in DMF.

A solution of the amine (17) is reacted with a substituted acetylchloride to form the corresponding substituted acylamide (18).

Alternatively, a solution of free amine (17) is reacted with a substituted sulphonylchloride to form the corresponding sulphonamide (19). The reaction takes place in THF and dimethylaminopyridine (DMAP) solution at room temperature for about four hours.

Additionally a solution of free amine (17) may be reacted with a substituted isocyanate to produce a desired compound (20). This may be converted, if desired, to a pharmaceutically acceptable salt. ##STR18##

One process is indicated by the sequence 2, 23, 24 of the scheme. The 2-adamantyloxycarbonyl-α-methyl-D-trytophan intermediate in ethyl acetate is treated sequentially with DCCI and HOBT and later reacted with an amine (12 in Scheme I) to produce a desired benzyl ester (23). This is reduced to the free carboxylic acid (24) using hydrogen and a 10% palladium on carbon catalyst for about four hours. The reaction mixture is filtered, washed and concentrated in vacuo to yield (24).

Another process is illustrated by sequence 2, 25, 26 and 27 or 28. In this process compound (2) is reacted with DCCI and PFP in ethyl acetate. After stirring for an hour at room temperature the mixture is reacted with the amino-azide (6 in Scheme I) to yield a compound (25). This is then dissolved in five percent acetic acid; ninety-five percent ethanol and converted to a crude amine acetate (26) by hydrogenation in the presence of a catalyst such as ten percent palladium in carbon.

Compound (26) may then be reacted with succinic anhydride to form the free carboxylic acid (28).

Also compound (26) is reacted with fumaryl dichloride to produce compound (27).

Compound (27) or (28) may be converted, if desired, to a pharmaceutically acceptable salt thereof. ##STR19##

The indole ethyl 2-carboxylate is protected on the indole nitrogen by tosylation to give (6) which is reduces by Red-A1 to the corresponding 2-hydroxymethyl compound (7). The alcohol (7) is converted into the corresponding bromide (8) using bromine and triphenylphosphine. The bromide (8) is used to alkylate the anion of the Schiff's base (8A) derived from the methyl ester of alanine to give the Schiff's base (9) as a racemate. The hydrolysis of the Schiff's base gives the free amine (10) which is condensed with 2-adamantylchloroformate to give the methyl ester (11) which is hydrolyzed with potassium hydroxide in ethanol followed by further acidic work up to give the free carboxylic acid (12).

This acid, which is the 2-indole analog of the intermediate (2) is also condensed with amines such as previously illustrated in Schemes I and V to produce final products, for example, condensation of (12) with phenylethylamine gives compound (13a) and with (S)-(-)-2-amino-3-phenyl-1-propanol to give the (13b) as a mixture of diastereoisomers. These are separated by chromatography to give diastereoisomer 1 and diastereoisomer 2 foam with Rf 0.70 and 0.65 in MeOH/CH2 Cl2 in ratio 1:9. ##STR20##

Scheme V below illustrates synthesis of preferred C-terminal side chains R3 and R4 used to prepare the final products illustrated in Scheme VI.

Thus the conversion of (35) to (37) is accomplished by condensing the isobutylformyl ester of (35) with 2-(trimethylsilyl)ethanol to give intermediate (36) followed by cleavage of the TMS group with TFA to give (37).

The oxime ester intermediate (40) is prepared by acylation of aminoacetophenone hydrochloric acid (38) with 2-(trimethylsilyl)ethylchloroformate in THF following by condensation with hydroxylamine hydrochloride and sodium acetate to give an oxime. Compound (39) was then prepared by adding methyl bromoacetate in the presence of 10% NaOH and TBAB in toluene. The trimethylsilylethyl group is then selectively removed with tetrabutylammonium fluoride.

Intermediate (42) is prepared from the alcohol (41) in the steps involving tosylation of the alcohol, displacement of the rosylate by sodium azide in DMF followed by catalytic reduction.

The tetrazole carboxylic acid intermediate (44) is prepared from the nitrile (43) in three steps by addition of azide to form a tetrazole which is protected by benzylation followed by hydrolysis of the methyl ester to the free carboxylic acid using an aqueous THF solution of lithium hydroxide.

The diene ester (47) is prepared from the BOC-protected phenylalanine (45) through aldehyde (46) using the Wittig reagent Ph3 PCHCHCHCO2 CH3.

The intermediate ether (50) is prepared from the chlorohydroxy compound (48) involving displacement of the chloride with sodium azide followed by alkylation of the anion of the hydroxyl group with methyl iodoacetate to give the azido ether (49) which is then reduced under catalytic conditions.

The ethyl ester (52) is prepared by catalytic hydrogenation of nitrile (51).

In Scheme V below R is methyl when Ar is phenyl and R is 2-(trimethylsilyl)ethyl when Ar is p-iodophenyl. ##STR21##

Scheme VI below shows the synthesis of compounds further illustrating preferred examples of R3 and R4 of formula I.

Key intermediate (2) is converted into the O-ether-linked side chain carboxylic acid (54) by condensation with the amine (50 of Scheme V) as described above, with subsequent hydrolysis.

Compound (65) with an α-pentanoic acid side chain is prepared by hydrogenation followed by hydrolysis of the unsaturated ester (64) which is prepared by condensation of flexible acid (2) with amine (47 of Scheme V).

The glycyl derivative (56) is prepared by condensation of the benzyl ester of glycine with the acid (55) followed by catalytic hydrogenation to remove the benzyl group. The acid (55) in turn is prepared from the flexible acid (2) by condensation with the amine (52 of Scheme V).

The oxime ether carboxylic acid (57) is also prepared from the flexible acid intermediate (2) by condensation with intermediate (40) (Scheme V) followed by hydrolysis of the ethyl ester with aqueous lithium hydroxide in THF.

The tetrazole (62) is prepared by condensation of the amine (60) with the benzylated tetrazole carboxylic acid (44 of Scheme V) followed by removal of the benzyl group by catalytic hydrogenation.

The intermediate amine (60) is prepared from the flexible acid (2) by condensation of the amine (42) of Scheme V followed by removal of the benzyloxycarbonyl group by catalytic hydrogenation.

The α-glycinate derivative (59) is prepared by condensation of the α-acetic acid derivative (58) with ethylglycinate followed by hydrolysis of the ethyl ester with 1M NaOH in ethanol.

The acid (58) is prepared from the key intermediate (2) by condensation with (37) of Scheme V (wherein R is methyl and Ar is phenyl) followed by hydrolysis of the methyl ester with aqueous lithium hydroxide in THF.

The α-acetic acid (53) is prepared from the key acid (2) by condensation with (39) of Scheme V (wherein R is 2-(trimethylsilyl)ethyl and Ar is p-iodophenyl) followed by removal of the 2-(trimethylsilyl)ethyl protecting group with tetrabutyl ammonium fluoride in THF. ##STR22##

Scheme VII below shows the synthesis of compound 71 which illustrates an example of formula I wherein R2 is the functional group CH2 CO2 Me.

The starting formyl tryptophan (66) is protected on the indole nitrogen by BOC and protected on the carboxylic acid as benzyl ester (67). The N-formyl group is then dehydrated with triphosgene to form the corresponding isonitrile of which the anion of which is formed on treatment with LDA and then alkylated with methyl bromoacetate to give (68).

The isonitrile (68) is hydrolyzed using ethanolic HCl to the corresponding amine which is directly converted to (69) by acylation with 2-adamantylchloroformate. The benzyl ester group of (69) is then selectively removed by hydrogenation using 10% palladium on carbon and the resulting free carboxylic acid (70) is then condensed with phenylethylamine to generate the final product (71). ##STR23##

Scheme VIII below illustrates the synthesis of a difunctionalized derivative of formula I when R3 is hydroxymethylene and R4 is hydroxyl. Intermediate (2) is condensed with L-(+)-threo-2-amino-1-phenyl-1,3-propandiol using the PFP ester of (2). ##STR24##

Scheme IX below illustrates a preferred mild procedure to prepare compound (82) when the TMS ester (81) is cleaved to the carboxylic acid (82) under mild conditions using tetrabutylammonium fluoride in THF. The scheme also illustrates the preparation of compound (80) by acetylation of amine (60K) with succinic anhydride in ethylacetate. ##STR25##

Compounds of the formula ##STR26## wherein R14 is a hydrogen atom or a N-protecting group (Boc, Cbz, Ts; preferably Ts), and R15 is ##STR27## are prepared using key intermediates of the present invention and are compounds of formula ##STR28## wherein R14 is a hydrogen atom or a protecting group. These are useful as intermediates in the preparation of compounds of formula I.

Compounds of formula I can be synthesized as shown in Schemes X and Scheme XI below; Compound 12, a key intermediate, is part of the instant invention.

The indole ethyl 2-carboxylate is protected on the indole nitrogen by tosylation to give 1 which is reduced by Red-Al to the corresponding 2-hydroxymethyl compound 2. The alcohol 2 is converted into the corresponding bromide 3 using bromine and triphenylphosphine. The bromide 3 is used to alkylate the anion of the Schiff's base 3A derived from the methyl ester of alanine to give the Schiff's base 4 as a racemate. The hydrolysis of 4 gives the free amine 5 which is condensed with 2-adamantylchloroformate to give the methyl ester 6 which is hydrolyzed with potassium hydroxide in ethanol followed by further acidic work up to give the free carboxylic acid 9. The hydrolysis of 6 with LiOH/aq. dioxane gives the carboxylic acid 7. The acid 9 is condensed with amines to produce final products, for example, condensation of 9 with phenylethylamine gives compound 10 and with (S)-(-)-2-amino-3-phenyl-1-propanol to give 11 as a mixture of diastereoisomers which are separated by chromatography to give diastereoisomer 1 and diastereoisomer 2. The condensation of 9 with the amine 12 (Scheme XI) gives 13 as a mixture of diastereoisomers. These are separated by chromatography to give 13A and 13B. Finally, the benzyl ester in 13A and 13B is hydrogenolyzed to form the desired product 14 as separated diastereoisomers 14A and 14B. ##STR29##

Another process for the preparation of compounds 94a (13a) and 94b (13b) (see Scheme XI) is illustrated in Scheme XII below. In this process the intermediate 9 is condensed with the amine 15 (R configuration) to produce compound 16 as a mixture of diastereoisomers. These are converted to the free amine 17 by removal of the benzyloxycarbonyl group by catalytic hydrogenation. The pure amines (mixture of diastereoisomers) are treated with benzyl-hemisuccinate (18) and CDI in dry THF at room temperature to produce 93 as a mixture of diastereoisomers. These are separated by chromatography to give diastereoisomer 1 (93a) and diastereoisomer 2 (93b). The benzyl ester in 93a and 93b is hydrogenolyzed to form the desired product of formula 14 as separated diastereoisomers A and B as in Scheme XI. ##STR30##

The biological activity of compounds of the present invention was evaluated employing an initial screening test which rapidly and accurately measured the binding of the tested compound to known CCK receptor sites. Specific CCK receptors have been shown to exist in the central nervous system. (See Hays et al, Neuropeptides 1:53-62, 1980; and Satuer et al, Science, 208:1155-1156, 1980.

In this screening test, the cerebral cortices taken from male CFLP mice weighing between 30-40 g were dissected on ice, weighed, and homogenized in 10 volumes of 50 mM Tris-HCl buffer (pH 7.4 at 0°-4° C.). The resulting suspension was centrifuged, the supernate was discarded, and the pellet was washed by resuspension in Tris-HCl buffer followed by recentrifugation. The final pellet was resuspended in 20 volumes of 10 nM Hepes buffer (pH 7.2 at 23° C.) containing 130 mM NaCl, 4.7 nM KCl, 5 nM MgCl2, 1 nM EDTA, 5 mg/mL bovine albumin, and bacitracin (0.25 mg/mL).

In saturation studies, cerebral cortical membranes were incubated at 23° C. for 120 minutes in a final volume of 500 μliter of Hepes incubation buffer (pH 7.2) together with 0.2-20 nM tritiated-pentagastrin (Amersham International, England).

In the displacement experiments, membranes were incubated with a single concentration (2 nM) of ligand, together with increasing concentrations (10-11 to 10-14 M) of competitive test compound. In each case, the nonspecific binding was defined as that persisting in the presence of the unlabeled octapeptide CCK26-33 (10-6 M).

Following incubation, radioactivity bound to membranes was separated from that free in solution by rapid filtration through Whatman GF/B filters and washed three times with 4 mL of ice cold Tris-HCl buffer. Filters from samples incubated with tritiated-pentagastrin were placed in polyethylene vials with 4 mL of scintillation cocktail, and the radioactivity was estimated by liquid scintillation spectrometry (efficiency 47-52%).

The specific binding to CCK receptor sites was defined as the total bound tritiated-pentagastrin minus the amount of tritiated-pentagastrin bound in the presence of 10-6 octapeptide, CCK26-33.

Saturation curves for specific tritiated-pentagastrin binding to mouse cortical membranes were analyzed by the methods of Scatchard (Ann. New York Acad. Sci. 51:660-672, 1949, and Hill (J. Physiol. 40:IV-VIII, 1910, to provide estimates for the maximum number of binding sites (Bmax) and the equilibrium dissociation constant (Ka).

In displacement experiments, inhibition curves were analyzed by either logit-log plots or the iterative curve fitting computer program ALLFIT (DeLean, Munson and Redbard, 1978) to provide estimates of the IC50 and nH (apparent Hill coefficient) values). (IC50 values were defined as the concentration of test compound required to produce 50% inhibition of specific binding.)

The inhibition constant (Ki) of the test compound was then calculated according to the Cheng-Prusoff equation: ##EQU1## where [L] is the concentration of radiolabel and Ka is the equilibrium dissociation constant.

The Ki /M values for several representative compounds of the present invention are present in Table III.

Compounds of the present invention are useful as appetite suppressants as based on the tests described hereinbelow.

In the Palatable Diet Feeding assay, adult male Hooded Lister rats weighing between 200-400 g were housed individually and trained to eat a palatable diet. This diet consisted of Nestles sweetened condensed milk, powdered rat food and rat water which when blended together set to a firm consistency. Each rat was presented with 20-30 g of the palatable diet for 30 minutes per day during the light phase of the light-dark cycle over a training period of five days. The intake of palatable diet was measured by weighing the food container before and after the 30-minute access period (limits of accuracy 0.1 g). Care was taken to collect and correct for any spillage of the diet. Rats had free access to pellet food and water except during the 30-minute test period.

After the training period, dose-response curves were constructed for CCK8 and several representative compounds of the present invention (n=8-10 rats per dose level). MPE50 values (±95% confidence limits) were obtained for the anorectic effects of these compounds and are shown in Table III.

In therapeutic use as appetite suppression agents, the compounds of the instant invention are administered to the patient at dosage levels of from about 200 to about 2800 mg per day.

NT = Not tested * MPE50 value = the dose of compound producing 50% of the maximum effect possible, which in these experiments would be zero food intake. (n)a = Number of assays

Male Hooded Lister rats (175-250 g) were housed individually and fasted overnight (free access to water). They were anesthetized with urethane (1.5 g/kg IP) and the trachea cannulated to aid spontaneous respiration. The stomach was perfused continuously using a modification of the original method of Ghosh & Schild in "Continuous recording of acid secretion in the rat", Br. J. Pharmac 13:54-61, 1956 as described by Parsons in "Quantitative studies of drug-induced gastric acid secretion". (Ph.D. Thesis, University of London, 1969). The cavity of the stomach was perfused at a rate of 3 mL/min with 5.4% w/v glucose solution through both the esophageal and body cannula. The fluid was propelled by a roller pump (Gilson, Minipuls 2), through heating coils to bring its temperature to 37±1° C. The perfusion fluid was collected by the fundic collecting funnel and passed to a pH electrode connected to a Jenway pH meter (PHM6). An output was taken from the pH meter to a Rikadenki chart recorder for the on-line recording of the pH of the gastric perfusate.

Pentagastrin was stored as a frozen aliquot and diluted to the required concentrations with sterile 0.9% w/v NaCl. Novel compounds were dissolved in sterile 0.9% w/v NaCl on the day of the experiment. Drugs were administered IV through a cannulated jugular vein as a bolus in a dose volume of 1 mL/kg washed in with 0.15 mL 0.9% w/v NaCl. Basal pH was allowed to stabilize before administration of compounds was begun. Typically 30 minutes elapsed between surgery and the first compound administration.

Compound (20) antagonized the stimulation of gastric acid secretion produced by a standard dose of 1 nmole/kg pentagastrin (FIG. 1). Compound (16) also attenuated the amount of gastric acid secreted in response to a 1 nmole/kg dose of pentagastrin (initial pentagastrin response 254 μmoles/1H+, after compound (16) (cumulative dose of 1.1 μmole/kg) 128 μmoles/1H+). With both compounds the antagonism was reversible with full recovery of the response to pentagastrin.

The compounds of the instant invention are also useful as antiulcer agents as discussed hereinbelow.

All animals were fasted for 24 hours before and throughout the experiment. Drug or vehicle was given 10 minutes before an oral dose of 1 mL of a 45-mg/mL suspension of aspirin in 0.5% carboxymethylcellulose (CMC).

The animals were sacrificed five hours after aspirin administration and the stomachs removed and opened for examination.

Gastric damage was scored as follows:

______________________________________

Score

______________________________________

1 Small hemorrhage2 Large hemorrhage3 Small ulcer4 Large ulcer5 Perforated ulcer

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The mean ulcer score in the saline control group was 12.1±6.85 (±SD). Treatment with ranitidine (15 mg/kg PO) inhibited ulcer formation by 74% giving an ulcer score of 3.2±2.35 (p<0.001 compared with controls). Treatment with [R-(R*,R*)-4-[[2-[[3-(1H-indol-3-yl)-2-methyl-1-oxo-2-[[(tricyclo[3.3.1.1. sup.3,7 ]-dec-2-yloxy)carbonyl]amino]propyl]-amino]-1-phenylethyl]amino]-4-oxobuta noic acid (10 mg/kg PO) resulted in an ulcer score of 6.3±4.14 (p<0.05 compared with controls), a 48% reduction in ulcer formation.

The specific dosages employed, however, may be varied depending upon the patient, the severity of the condition being treated, and the activity of the compound employed. Determination of optimum dosages is within the skill of the art.

The compounds of the instant invention are also useful as anxiolytic agents as described and discussed below.

In FIG. 2 the number of mice was 5 and the pretreatment time was 40 minutes. The compound was given p.o. in 0.1, 1, and 10 mg/kg doses.

The apparatus was an open-topped box, 45 cm long, 27 cm wide, and 27 cm high, divided into a small (2/5) area and a large (3/5) area by a partition that extended 20 cm above the walls. There was a 7.5×7.5 cm opening in the partition at floor level. The small compartment was painted black and the large compartment white. The floor of each compartment was marked into 9 cm squares. The white compartment was illuminated by a 100-watt tungsten bulb 17 cm above the box and the black compartment by a similarly placed 60-watt red bulb. The laboratory was illuminated with red light.

All tests were performed between 13 hundred hours, 0 minutes and 18 hundred hours, 0 minutes. Each mouse was tested by placing it in the center of the white area and allowing it to explore the novel environment for five minutes. Its behavior was recorded on videotape and the behavioral analysis was performed subsequently from the recording. Five parameters were measured: the latency to entry into the dark compartment, the time spent in each area, the number of transitions between compartments, the number of lines crossed in each compartment, and the number of rears in each compartment.

In this test an increase in the time spent in the light area is a sensitive measure of, that is directly related to, the anxiolytic effects of several standard anxiolytic drugs. Drugs were dissolved in water or saline and administered either subcutaneously, intraperitoneally, or by mouth (PO) via a stomach needle.

Compound (20) and compound [R-(R*,R*)]-4-[[2-[[3-(1H-indol-3-yl)-2-methyl-1-oxo-2-[[(tricyclo[3.3.1.s up.3,7 ]dec-2-yloxy)carbonyl]amino]propyl]amino]-1-phenylethyl]amino]-4-oxobuteno ic acid were active by the subcutaneous route. Control animals showed 3% crossings into the dark area over five-minute measurement periods. Mice treated with 1 mg/kg (SC) of compound (20) showed 85 crossings into the light area and only 24 crossings into the dark area, a significant (p<0.01) difference from the control anxious mice. Diazepam (0.25 mg/kg IP) had an effect identical to compound (20) in the same experiment. In additional experiments compound [R-(R*,R*)]-4-[[2-[[3-(1H-indol-3-yl)-2-methyl-1-oxo-2-[[(tricyclo[3.3.1.s up.3,7 ]-dec-2-yloxy)carbonyl]amino]propyl]amino]-1-phenylethyl]amino]-4-oxobuten oic acid (a mg/kg SC) and compound (20) (1 mg/kg PO) significantly (p<0.01) increased the time spent in the light area of the test box.

The compounds of the instant invention are useful as antipsychotic agents. Compound (20) (which is shown as compound (24) in Scheme III) and compound (20A) were tested for their ability to reduce the effects of intra-accumbens amphetamine in the rat as described hereinafter.

Male Sprague Dawley (CD) Bradford strain rats were used. The rats were housed in groups of five at a temperature of 21°±2° C. on a 12 hour light-dark cycle of lights-on between 07 hours 00 minutes and 20 hours 00 minutes. Rats were fed CRM diet (Labsure) and allowed water ad libitum.

Rats were manually restrained and the stylers removed. Intracerebral injection cannulae, 0.3 mm diameter, were inserted and drugs delivered in a volume of 0.5 μl over 5 seconds (a further 55 seconds was allowed for deposition) from Hamilton syringes attached via polythene tubing to the injection units. Animals were used on a single occasion only.

Behavioral experiments were conducted between 07 hours 30 minutes and 21 hours 30 minutes in a quiet room maintained at 22°±2° C. Rats were taken from the holding room and allowed one hour to adapt to the new environment. Locomotor activity was assessed in individual screened Perspex cages (25×15×15 cm (high) (banked in groups of 30) each fitted with one photocell unit along the longer axis 3.5 cm from the side; this position has been found to minimize spurious activity counts due to, for example, preening and head movements when the animal is stationary. Interruptions of the light beam were recorded every 5 minutes. At this time animals were also observed for the presence of any nonspecific change in locomotor activity, e.g., sedation, prostration, stereotyped movements, that could interfere with the recording of locomotor activity.

The abilities of the compounds (20) and (20A) to inhibit the hyperactivity caused by the injection of amphetamine into the nucleus accumbens of the rat was measured.

An increase in locomotor activity followed the bilateral injection of amphetamine (20 μg) into the nucleus accumbens; peak hyperactivity (50 to 60 counts 5 minutes-1) occurred 20 to 40 minutes after injection.

Intraperitoneal injection of the rats with compound (20A) (20 mg/kg or 30 mg/kg) or compound (20) (10 mg/kg) reduced the hyperactivity caused by the intra-accumbens injection of amphetamine (FIGS. 3 and 4). This test is known to be predictive of antipsychotic activity (Costall, Domeney & Naylor & Tyers, Brit J Pharmac 92:881-894).

FIG. 3 shows the antagonism of intra-accumbens amphetamine (20 μg) by compound (20A). The amphetamine control is shown by -.quadrature.-, the vehicle by -.diamond-solid.-, the -Δ- shows compound (20) at 1 mg/kg IP and -Δ- shows the compound at 10 mg/kg IP. The number tested was five. The *P is <0.05. The time in minutes is shown versus activity (counts/5 minutes).

FIG. 4 shows the antagonism of intra-accumbens amphetamine (20 μg) for compound (20). The figure is described as for FIG. 3 above.

The compounds of the instant invention prevent and treat the withdrawal response produced when chronic treatment by a drug is stopped or when alcohol abuse is stopped. These compounds are therefore useful as therapeutic agents in the treatment of chronic drug or alcohol abuse as discussed and described below.

The effect of the compounds of the instant invention is illustrated, for example, in the mouse "light/dark box" test in FIGS. 5-12.

In FIG. 5, five animals were given nicotine, 0.1 mg/kg i.p. b.d. for 14 days. After a 24-hour withdrawal period, compound (20) was given at 1.0 mg/kg i.p. b.d. The increased time spent in the light area is a sensitive measure of the effect of compound (20) as an agent to treat withdrawal effects from nicotine.

FIG. 6 illustrates the effect of long-term treatment and withdrawal from nicotine using compound (20A). Five mice were given nicotine at 0.1 mg/kg i.p. b.d. for 14 days. After a withdrawal period of 24 hours, compound (20A) was given at 10 mg/kg i.p. b.d. The effect of compound (20A) can be seen in the increase of time spent in the light area.

FIG. 7 illustrates the effect of long-term treatment and withdrawal from diazepam with intervention with compound (20). Five mice were given diazepam, at 10 mg/kg i.p. b.d. for seven days. Withdrawal was for a 24-hour period; compound 20 was given at 1.0 mg/kg i.p. b.d. The increased time spent in the light section shows the effect of compound (20).

FIG. 8 illustrates the effect of compound (20A) on the long-term treatment and withdrawal from diazepam. Five mice were given diazepam at 10 mg/kg i.p. b.d. for seven days. After a withdrawal period of 24 hours, compound (20A) was given at 10 mg/kg i.p. b.d. The amount of time spent in the light section after compound (20A) is administered demonstrates the effectiveness of the compound.

FIG. 9 illustrates the effect compound (20A) on the long-term treatment and withdrawal from alcohol. Five mice were given alcohol in drinking water 8% w/v for 14 days. After a withdrawal period of 24 hours, compound (20) was given at 1.0 mg/kg i.p. b.d. The amount of time spent in the light section after the compound was administered demonstrates the effectiveness of the compound.

FIG. 10 shows the effect of compound (20A) on long-term treatment and withdrawal from alcohol. Five mice were given alcohol in drinking water, 8% w/v for 14 days. After a withdrawal period of 24 hours, compound (20A) was given at 10 mg/kg i.p. b.d. The increased time spent in the light section shows the effect of compound (20A) on the mice.

FIG. 11 illustrates the effectiveness in the long-term treatment and withdrawal from cocaine. Five mice were given cocaine as 1.0 mg/kg i.p. b.d. for 14 days. The increased time in the light section illustrates the effectiveness of compound (20) in the treatment.

FIG. 12 shows the effect of long-term treatment and withdrawal from cocaine with the intervention of compound (20A). Five mice were given cocaine at 1.0 mg/kg i.p. b.d. for 14 days after a withdrawal period of 24 hours, compound (20a) was given at 1.0 mg/kg i.p. b.d. The effect of intervention with compound 20A is shown by the increase in time spent in the light section.

FIG. 13 shows the anxiolytic effects of compound 20 in the Rat Social Interaction Test on a dose range of 0.001 to 1.0 mg/kg when paired rats are dosed s.c. The anxiolytic effect of compound 20 are indicated by the increase in time spent in social interaction compared with the control value C. (Costall, B., University of Bradford)

FIG. 14 shows the anxiolytic effects of compound 20 in the Rat Elevated X-Maze Test on a dose range of 0.01 to 1.0 mg/kg s.c. The anxiolytic effect is indicated by the time spent in the open arm end section compared with control C.

FIG. 15 shows the anxiolytic effects of five compounds of the invention as compared to the vehicle alone and to compound 20 in the Rat Elevated X-Maze Test. The dose was equivalent to 0.1 mg/kg p.o. compound 20.

FIG. 16 shows that compound 20 depresses the flexor response in a stimulated spinalized decerebrated rat preparation similar to morphine. The effect (lower diagram) of giving compound 20 with morphine greatly potentiates the effect which lasts for 3 hours.

FIG. 17 shows that compound 20 given (in saline) at 10 mg/kg/day effects the mean tumor volume as compared to the control .quadrature. (saline). The control number was 13 and the compound 14.

Compound 20 is a highly selective and a potent CCK B receptor antagonist in the central nervous system. FIG. 17 shows compound 20 capable of inhibiting the in vitro and in vivo proliferation of a human colorectal cell line, LoVo.

One×106 LoVo cells in 0.1 mL serum-free RPMI were injected subcutaneously into the backs of 27 male nude mice. Xenografts were grown for 10 days prior to treatment, then randomly allocated to receive twice daily garage with either 0.1 mL saline alone or containing 10 mg/kg/day of compound 20 for 20 days. Bidirectional tumor diameter was measured using vernier calipers and converted to volumes [(1/2×length) +diameter2 ]. The animals were sacrificed on Day 30. The protocol was approved by the UNSW Ethics committee.

In the in vivo study (FIG. 17) there was a significant divergence of tumor size between control and treated animals from Day 21 of treatment which was maintained over the 20-day experiment (p<0.05, ANOVA). The tumor volume at Day 30 was reduced by 53% by compound 20 compared to control. Unstimulated, in vitro growth of LoVo and the 53% inhibition of in vivo growth over 20 days is shown.

Therefore, compound 20 is capable of markedly inhibiting the basal growth of LoVo at concentrations which should be achieved in vivo by oral therapy and may be of use in the treatment of some human colorectal cancers.

For preparing pharmaceutical compositions from the compounds of this invention, inert, pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, and suppositories.

A solid carrier can be one or more substances which may also act as diluents, flavoring agents, solubilizers, lubricants, suspending agents, binders, or tablet disintegrating agents; it can also be an encapsulating material.

In powders, the carrier is a finely divided solid which is in a mixture with the finely divided active component. In tablets, the active component is mixed with the carrier having the necessary binding properties in suitable proportions and compacted in the shape and size desired.

For preparing suppository preparations, a low-melting wax such as a mixture of fatty acid glycerides and cocoa butter is first melted and the active ingredient is dispersed therein by, for example, stirring. The molten homogeneous mixture is then poured into convenient sized molds and allowed to cool and solidify.

The term "preparation" is intended to include the formulation of the active component with encapsulating material as a carrier providing a capsule in which the active component (with or without other carriers) is surrounded by a carrier which is thus in association with it. Similarly, cachets are included.

Tablets, powders, cachets, and capsules can be used as solid dosage forms suitable for oral administration.

Liquid form preparations include solutions, suspensions, and emulsions. Sterile water or water-propylene glycol solutions of the active compounds may be mentioned as an example of liquid preparations suitable for parenteral administration. Liquid preparations can also be formulated in solution in aqueous polyethylene glycol solution.

Aqueous solutions for oral administration can be prepared by dissolving the active component in water and adding suitable colorants, flavoring agents, stabilizers, and thickening agents as desired. Aqueous suspensions for oral use can be made by dispersing the finely divided active component in water together with a viscous material such as natural synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose, and other suspending agents known to the pharmaceutical formulation art.

Preferably the pharmaceutical preparation is in unit dosage form. In such form, the preparation is divided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, the package containing discrete quantities of the preparation, for example, packeted tablets, capsules, and powders in vials or ampoules. The unit dosage form can also be a capsule, cachet, or tablet itself, or it can be the appropriate number of any of these packaged forms.

Examples A-I are illustrative of methods of preparing the precursors or intermediates of the final products which are illustrated in Examples 1-45 (corresponding to compounds 1-45 described in the figures and experimental) but not as numbers corresponding to the numbers given in the schemes.

INTERMEDIATE EXAMPLE A

N-[(1-Adamantyloxy)carbonyl]-α-methyl-DL-tryptophan

To a solution of α-methyl-DL-tryptophan (2.18 g, 10 mmol) in 1M NaOH solution (10 mL) at 0° C. was added NaHCO3 (0.92 g, 11 mmol) followed by a solution of 1-adamantylfluoroformate (2.18 g, 11 mmol) in 1,4 dioxan (10 mL). The mixture was stirred at 0° C. for one hour and then 24 hours at room temperature.

To a solution of N-[(9H-fluoren-9-ylmethyloxy)carbonyl]-α-methyl-DL-tryptophan (8.80 g, 20 mmol) in dry ethyl acetate (350 mL) was added pentafluorophenol (3.68 g, 20 mmol) and stirred for 10 minutes. The reaction mixture was cooled to 0° C. and a solution of dicyclohexylcarbodiimide (20 mmol) in ethyl acetate (25 mL) was added dropwise. This solution was stirred for one hour at 0° C. then at room temperature for four hours before leaving it at 4° C. overnight. The mixture was filtered and the precipitate washed with cold ethyl acetate (30 mL) and a solution of 2-phenethylamine (2.66 g, 22 mmol) in ethyl acetate (30 mL) was added dropwise to the combined filtrates. The mixture was left to stir for 48 hours at room temperature. The reaction mixture was filtered and the residue washed with cold ethyl acetate (2×30 mL) to give the title compound (3.73 g, 75%). The filtrates were combined and the solvent removed in vacuo and taken up again in ethyl acetate (5 mL) to give a second crop of 1.67 g (15%), a total of 90% yield as a white solid, mp 179°-181° C. (EtOAc); IR (film) 1708, 1652 cm-1 ; NMR (DMSO d6) δ1.30 (3H, s), 2.64 (2H, t, J 7.2 Hz), 3.2-3.3 (4H, m), 4.19 (1H, t, J 6.7 Hz), 4.25-4.40 (2H, m), 6.9-7.9 (20H, m), 10.8 (1H, s).

A solution of N-[(9H-fluoren-9-ylmethoxy)carbonyl]-α-methyl-DL-tryptophan (10 g, 22.7 mmol) and pentafluorophenol (4.18 g, 22.7 mmol) in dry ethyl acetate (200 mL) was treated dropwise at 0° C. with a solution of dicyclohexylcarbodiimide (4.9 g, 24 mmol) in ethyl acetate (20 mL). This was allowed to warm to room temperature and stirred for a further hour. This mixture was then treated with a solution of L-phenylalaninol (3.775 g, 25 mmol) in ethyl acetate (15 mL) dropwise and the resultant mixture left stirring for 15 hours. This mixture was filtered and the filtrate washed sequentially with 2M citric acid solution, 1M NaOH solution, saturated NaHCO3 solution then water before being dried over MgSO4 and concentrated to an oil in vacuo. This oil was subjected to silica gel chromatography using 4% MeOH: 96% CH2 Cl2 as eluant to give the title compound (11.7 g, 90%), as a white solid and a mixture of two diastereoisomers. These two diastereoisomeric forms were separated by further chromatographic purification using 1% i PrOH, 99% CHCl3 as the eluant to give equal amounts of the pure diastereoisomers as white amorphous solids.

To a solution of N-[(tricyclo[3.3.1.13,7]dec-1yloxy)carbonyl]-α-methyl-DL-tryptophan (1.0 g, 2.5 mmol) in 1,4 dioxan (40 mL) was added a solution of pentafluorophenol (0.465 g, 2.5 mmol) in 1,4 dioxan (5 mL) and stirred at room temperature for 15 minutes, cooled to 0° C. and a solution of dicyclohexylcarbodiimide (0.547 g, 2.65 mmol) in 1,4 dioxan (10 mL) was added dropwise. This was allowed to stir at room temperature for two hours before phenethylamine (0.333 g, 2.75 mmol) was added in one portion. The mixture was left stirring for 24 hours.

A solution of the tosylate from Step 1 (3 g, 7.4 mmol) in anhydrous, N,N-dimethylformamide (20 mL) was treated with sodium azide (0.52 g, 8 mmol) and the resulting mixture heated to 120° C. for 1.5 hours. This was allowed to cool and then concentrated in vacuo. The syrup was diluted with ethyl acetate and washed with water (X3). The organic phase was dried over MgSO4 and evaporated to give the azide (1.31 g) as a slightly impure waxy solid, and used as such in Step 3, mp 44°-45° C.; IR (film) (inter alia) 3341, 2978, 2101 and 1698 cm-1.

A solution of [R-(R*,S*)]-tricyclo[3.3.1.13,7 ]dec-2-yl-[2-[[1-(azidomethyl)-2-phenylethyl]amino]-1-(1H-indol-3-ylmethyl )-1-methyl-2-oxoethyl]carbamate (0.2 g, 0.36 mmol) in 5% acetic acid:95% ethanol (100 mL) was treated with 10% palladium on carbon (0.02 g, 10% w/w) and put under an atmosphere of hydrogen at a pressure of 51 psi at 30° C. with agitation. After no more hydrogen was seen to be taken up, the mixture was filtered over celite and concentrated in vacuo to a foam (0.25 g) which was used immediately in Step 6. IR (film 1676 br cm-1.

In an analogous manner but using 1-(S)-2-endobornyloxy-carbonyl-[D]α-methyltryptophan, [1S-[1α,2β[S*(S*)],4α]]-4-[[2-[[3-(1H-indol-3-yl)-2-methy l-1-oxo-2-[[[(1,7,7-trimethylbicyclo[2.2.1]hept-2-yl)oxy]carbonyl]amino]pro pyl]amino]-1-phenylethyl]amino]-4-oxobutanoic acid was prepared.

A solution of the tosylate (4.67 g, 11.9 mmol) in anhydrous DMF (60 mL) was treated with sodium azide (868 mg, 13.4 mmol). The mixture was heated to 120° C. for 1.5 hours. After cooling, the solution was poured into water (250 mL), and the aqueous layer extracted with an equal volume of ether. The ethereal phase was washed with water, dried over MgSO4 and the solvent removed in vacuo to yield the desired azide as a white crystalline solid, used without further purification (2.37 g, 70%), mp 76°-78° C.; IR (film) 3380, 2095, 1682, and 1515 cm-1 ; NMR (CDCl3) δ1.44 (9H, s), 3.76 (2H, m), 4.87 (1H, br.s), 5.03 (1H, br.s), 7.30-7.40 (5H, m).

Step 3

A solution of the azide (6.44 g, 24.6 mmol) in anhydrous ethyl acetate (100 mL) was subjected to an atmosphere of hydrogen at a pressure of 45 psi over Lindlar catalyst (2.58 g, 40% w/w) for 6 hours at room temperature. After this time the reaction mixture was filtered through filter aid and washed through with more ethyl acetate. The crude product, in solution, was used immediately in the next step of the reaction sequence. IR (film) 3350, 3000, and 1696 cm-1 ; NMR (CDCl3) δ1.43 (9H, s), 2.10 (2H, br.s), 3.10 (2H, br.s), 4.70 (1H, m), 5.45 (1H, br.s), 7.25-7.40 (5H, m).

The N-BOC-protected sulphoxide (462 mg, 1.25 mmol) was stirred in dichloromethane containing trifluoroacetic acid (5 mL of 1:1 mixture) for 1 hour at room temperature. All volatiles were removed in vacuo to give a syrup which was used without further purification (479 mg).

A solution of the azido ester from Step 2 (247 mg, 1.05 mmol) and 10M HCl solution (0.53 mL, 5.3 mmol) in absolute EtOH (50 mL) was reduced over 10% Pd/C (25 mg) at 40° C. under an atmosphere of H2 at 45 psi for 5 h. The catalyst was filtered off and the solvent removed in vacuo to give the amine hydrochloride (287 mg) which was without further purification in the next step; IR (film) 1738 cm-1.

To a stirred solution of methyl-3-(t-butyloxycarbonyl-amino)-4-phenylbutyrate (4.16 g, 14.19 mmol) from Step 2 in CH2 Cl2 (10 mL) was added trifluoroacetic acid (10 mL). After stirring for 1 h at room temperature the solvents were removed in vacuo giving the desired amine as an oil which was used without further purification in the next step.

To an ice-cooled solution of the combined tautomeric forms of the benzyl tetrazole from Step 2 (248 mg, 1.0 mmol) in THF (15 mL) was added 0.1M LiOH solution (10.6 mL, 1.0 mmol) dropwise over 2 h. The reaction mixture was then slowly allowed to warm to room temperature over 16 h. After this time the reaction was acidified to pH3 with 1M HCl and concentrated in vacuo. The residue was partitioned between water and EtOAc and the organic layer was dried (MgSO4) and concentrated in vacuo to yield the desired acid as a colourless liquid (151 mg, 65%) and as a mixture of two tautomers of the benzyl tetrazole; IR (film) 2600-3600, 1729 cm-1 ; NMR (CDCl3) δ2.90 (α3H, m) and 3.20 (α1H, t, J 7 Hz), 5.55 and 5.65 (2H, s), 7.35 (5H, s).

To an ice-cooled solution of the combined tautomeric forms of the benzyl tetrazole from Step 2 (248 mg, 1.0 mmol) in THF (15 mL) was added 0.1M LiOH solution (10.6 mL, 1.0 mmol) dropwise over 2 h. The reaction mixture was then slowly allowed to warm to room temperature over 16 h. After this time the reaction was acidified to pH3 with 1M HCl and concentrated in vacuo. The residue was partitioned between water and EtOAc and the organic layer was dried (MgSO4) and concentrated in vacuo to yield the desired acid as a colourless liquid (151 mg, 65%) and as a mixture of two tautomers of the benzyl tetrazole; IR (film) 2600-3600, 1729 cm-1 ; NMR (CDCl3) δ2.90 (≉3H, m) and 3.20 (≉1H, t, J 7 Hz), 5.55 and 5.65 (2H, s), 7.35 (5H, s).

Methyl-4-bromocrotonate (4.48 g, 25 mmol) and triphenylphosphine (6.55 g, 25 mmol) were heated together at 150° C. for 25 min. Recrystallization of the brown residue from EtOH/Et2 O gave the phosphonium salt (5.76 g, 52%) as an off white solid; mp 180°-181° C.

Step 4

To a stirred solution of the phosphonium salt from Step 3 (1.91 g, 4.33 mmol) in water (100 mL) was added dropwise 1M NaOH (4.5 mL, 4.5 mmol). After 10 min the product was extracted into CH2 Cl2 (50 mL) which was dried over MgSO4, filtered and the solvents removed in vacuo. The residue was dissolved in hot EtOAc and insoluble material filtered off. The volume of the filtrate was reduced and 40:60 petrol added causing the yield to precipitate out (0.86, 55%); mp 132°-143° C.

To a stirred solution of the ester from Step 5 (335 mg, 1 mmol) in CH2 Cl2 (5 mL) was added trifluoroacetic acid (5 mL). After 1 h at room temperature the solvents were removed in vacuo to give the desired amine as a residue which was used without further purification in the next step.

To a stirred suspension of sodium hydride (3.7 g, 120 mmol, 80% in paraffin oil) in dry THF (75 mL), a solution of indol-2-carboxylic acid ethyl ester (18.9 g, 100 mmol) in dry THF (75 mL ) was added in 1 hour with stirring while the inner temperature was maintained under 30° C. The reaction mixture was stirred for 30 min. and then a solution of p-toluenesulphonyl chloride (22.9 g, 120 mmol) in dry THF (75 mL) was added dropwise to the stirring reactant. After two hours stirring at room temperature and one hour at 45° C. the solvent was evaporated in vacuo and the residue partitioned between water and ethyl ether. The organic phase was dried over MgSO4 and the solvent evaporated to leave a solid which was recrystallized from diisopropyl ether (26.8g, 78%), m.p. 92°-95° C.

Step 2

2-Hydroxymethyl-1-(4-methylphenyl)sulfonyl-1H-indole

To stirred solution of Red-Al (sodium dihydrobis(2-methoxyethoxy)aluminate ≉70% in toluene) (30 mL) in dry THF (100 mL) cooled at 5° C. and under nitrogen was added dropwise and at this temperature a solution of compound of step 1 (26,8 g, 78 mmol) in dry THF (75 mL). After stirring one hour at 5° C. and then one hour at room temperature the mixture was cooled at 10° C. and treated dropwise with 2N NaOH, to effect hydrolysis of the intermediate complex. The organic phase was separated and the solvent in vacuo evaporated. The residue was solved in ethyl ether, the solution washed with water, dried over MgSO4 and evaporated to give the required alcohol (23.3 g, 98%) as a yellow oil; IR (film) 3500, 1597 cm-1.

Step 3

2-Bromomethyl-1-(4-methylphenyl)sulfonyl-1H-indole

To a solution of triphenylphosphine (20.2 g, 77 mmol) in dry CH2 Cl2 (80 mL) was added dropwise a solution of bromine (11.9 g, 77 mmol) in dry CH2 Cl2 (40 mL). The stirring was continued for one hour and then a solution of compound of step 2 (23.2 g, 77 mmol) in dry CH2 Cl2 (40 mL) was added dropwise. The resulting mixture left stirring for 12 hours. After removing the solvent the residue was taken up in ethyl acetate and washed with water. The organic extract was dried over MgSO4 and the solvent evaporated in vacuo. The residue was chromatographed over silica gel using toluene as eluant to give a yellow oil (21.0 g, 75 %); IR (film) 1600 cm-1, MS ((70 eV): m/z 363 (M+,12.6), 129 (100).

To a stirred solution of KOt.Bu (5.1 g, 45 mmol) in dry THF (25 mL) cooled at -40° C. was added dropwise at this temperature a solution of N-(phenylmethylene)-DL-alanine methyl ester (8.7 g, 45 mmol) in dry THF (40 mL) under nitrogen. The mixture was stirred one hour at -40° C. and then was added dropwise maintaining the temperature a solution of compound of step 3 (16.5g, 45 mmol) in dry THF (50 mL). After the addition was completed the mixture was stirred 2 hours at -20° C., then allowed to warm to room temperature and left overnight. The solvent was evaporated in vacuo given a resin, which on trituration with ethyl ether and water gave the required compound (16.5 g, 75%) as a white solid, m.p. 151°-154° C.

A suspension of compound of step 4 (16.1 g, 34 mmol) in ethanol (100 mL) and 2N hydrochloric acid (20 mL) was stirred overnight. After removing the solvent in vacuo the residue was suspended in water (400 mL), made basic with Na2 CO3, extracted with ethyl ether and dried over MgSO4. The solvent was evaporated providing an oil. This was subjected to silica gel chromatography using ethyl acetate/toluene 8:92 (v/v) then methanol/toluene 1:99 (v/v) as eluants to give the required compound (9.9 g, 75%) as an oil; IR (film) 1735 cm-1.

To a stirred solution of compound of step 5 (9.9 g, 25 mmol) in dry THF (100 mL) was added a solution of 2-adamantylchloroformate (6.4 g, 30 mmol) in dry THF (15 mL) dropwise followed by a solution of triethylamine (6.1 g, 56 mmol) in dry THF (15 mL). After one hour stirring, the reaction mixture was filtered and the solvent removed in vacuo. The residue was stirred with a mixture of light petroleum (100 mL) and ethyl ether (20 mL) to give the required compound as a colourless solid, which was removed by filtration (13.9 g, 96%), m.p. 119°-122° C.

A mixture of compound of Step 6 (6.8 g, 12 mmol) and KOH (2.7 g, 48 mmol) in ethanol (100 mL) was stirred for 60 hours at 70° C. After removing the solvent in vacuo the residue was partitioned between water (150 mL) and ethyl ether. The clear water phase was separated, acidified to pH 4.5 when an oil precipitated out which slowly solidified. The solid was collected by filtration, washed successively with water and dried to give the desired carboxylic acid (3.9 g, 81%) as a white solid, m.p. 210°-216° C.

Step 8

A mixture of compound of Step 7 (0.53 g, 1.3 mmol) and 1,1'-carbonyldiimidazole (0.22 g, 1.3 mmol) in dry THF (8 mL) was stirred for one hour. To this mixture was then added dropwise a solution of 2-phenethylamine (0.17 g, 1.4 mol) in dry THF (4 mL). After stirring overnight the solvent was evaporated in vacuo. The residue was solved in ethyl ether, washed with water, dried over MgSO4 and the solvent evaporated to leave a colourless foam which was crystallized from diisopropylether to yield the title compound (0.42 g, 64%), m.p. 168°-169° C. PAC EXAMPLE 46A+B

Method was as described for Example 45 above but instead using (S)-(--)-2-amino-3-phenyl-1-propanol in Step 8. The crude residue was chromatographed over silica gel using 1% MeOH: 99% CH2 Cl2 as eluant.

To a stirred solution of the protected ester from Step 1 (0.212 g, 0.60 mmol) in CH2 Cl2 (2 mL) was added TFA (2 mL). After 1 hour at room temperature the solvent was removed in vacuo. This gave the product as a syrup which was used without further purification.

To a stirred solution of the ester from Step 1 (0.25 g, 0.82 mmol) in CH2 Cl2 (2 mL) was added TFA (2 mL) and the mixture stirred for 1 hour at room temperature. Removal of the solvents in vacuo gave the product as a syrup which was used without further purification in Step 3.

A solution of DL-tryptophan methyl esterbenzaldimine (4.0 g, 13 mmol) in 30 mL THF was added over 15 minutes to a mixture of 20.2 mL lithiumdiisopropylamide (10% suspension in hexan) and 70 mL dry THF, cooled to -10° C. under nitrogen atmosphere. The stirring was continued for an additional 45 minutes, keeping the temperature at -10° C. A solution of trimethylsilylethoxymethylchloride (2.2 g, 13.2 mmol) in 5 mL THF was added and the mixture stirred overnight at room temperature. The reaction mixture was decomposed with 100 mL distilled water, extracted with ethyl acetate (3×100 mL), and the organic solvent was removed in vacuo. The resulting oily residue was treated with 30 mL 1N hydrochloric acid for 1 hour at room temperature after which the reaction mixture was made basic with sodium bicarbonate and extracted with ethyl acetate (3×100 mL). The organic layer was dried over Na2 SO4, evaporated to give the crude product which was separated by flash chromatography on silica gel using a mixture of toluene/ethanol 500:30 (v/v) as elution solvent. The fractions, containing the main product (TLC on silica gel, toluene/ethanol 10:2 (v/v), Rf 0.38) were combined and evaporated to dryness in vacuo. Trituration of the oily residue with diethyl ether gave 2.0 g (44%) of α-trimethylsilylethoxymethyl- DL-tryptophan methyl ester, mp 113°-115° C.

A mixture of α-trimethylsilylethoxymethyl-DL-tryptophan methyl ester (1.0 g, 2.8 mmol), diisopropylethylamine (0.4 g, 3 mmol) and 2-adamantylchloroformate (0.65 g, 3 mmol) in 20 mL dry THF was stirred at room temperature for 4 hours. The reaction mixture was diluted with distilled water and extracted with ethyl acetate (4×50 mL). The organic extract was washed with brine and dried over Na2 SO4. Evaporation of the organic solvent gave the title compound as a colorless foam (1.0 g, 67.8%). -[(2-Adamantyloxy)carbonyl]-α-trimethylsilylethoxymethylmethyl-DL-tr yptophan

A mixture of N-[(2-adamantyloxy)carbonyl]-α-trimethylsilylethoxymethyl-DL- tryptophan methyl ester (4.5 g, 8.5 mmol), LiOH (0.22 g, 9.1 mmol), dioxane (90 mL), and water (30 mL) was stirred at 60° C. for 16 hours. After cooling, the reaction mixture was acidified to pH 4 with 1N hydrochloric acid and extracted with ethyl acetate. The organic extract was dried over Na2 SO4 and then concentrated in vacuo. Trituration of the oily residue with diethyl ether gave the title compound as a white solid (4.0 g, 91.7%), mp 203° C. (dec.).

A solution of N-[(2-adamantyloxy)carbonyl]-α-trimethylsilylethoxymethyl-DL-tryptop han (0.6 g, 1.17 mmol) and N,N'-carbonyldiimidazol (0.21 g, 1.3 mmol) in 20 mL dry THF was stirred at room temperature for 48 hours. Then 2-phenethylamine (0.15 g, 1.3 mmol) was added to the reaction mixture and the stirring continued for an additional 24 ours. After dilution with distilled water, the product was extracted with ethyl acetate and separated by flash chromatography on silica gel using a mixture of n-hexane/ethyl acetate (2:1, v/v) as elution solvent. The desired compound was eluated from the column at first. The product was obtained as a colorless solid (0.3 g, 41.65), mp 75°-80° C.

EXAMPLE 89

α-Hydroxymethyl-DL-tryptophan methyl ester

α-Trimethylsilylethoxymethyl-DL-tryptophan methyl ester (1.0 g, 2.8 mmol) was stirred for 48 hours at room temperature in trifluoroacetic acid (10 mL). After evaporation of the acid in vacuo, the oily residue was treated with aqueous sodium bicarbonate and extracted with ethyl acetate. The organic layer was dried over Na2 SO4 and evaporated to give an oil. Trituration with ethyl acetate gave 0.45 g (655) of α-hydroxymethyl-DL-tryptophan methyl ester, mp 148°-149° C.

To a stirred suspension of sodium hydride (3.7 g, 120 mmol, 80% in paraffin oil) in dry THF (75 mL), a solution of indol-2-carboxylic acid ethyl ester (18.9 g, 100 mmol) in dry THF (75 mL) was added in 1 hour with stirring while the inner temperature was maintained under 30° C. The reaction mixture was stirred for 30 minutes and then a solution of p-toluenesulphonyl chloride (22.9 g, 120 mmol) in dry THF (75 mL) was added dropwise to the stirring reactant. After 2 hours stirring at room temperature and 1 hour at 45° C. the solvent was evaporated in vacuo and the residue partitioned between water and ethyl ether. The organic phase was dried over MgSO4 and the solvent evaporated to leave a solid which was recrystallized from diisopropyl ether (26.8 g, 78%), mp 92°-950° C.

2-Hydroxymethyl-1-(4-methylphenyl)sulfonyl-1H-indole

To a stirred solution of Red-Al (sodium dihydrobis(2-methoxyethoxy)aluminate .about.70% in toluene) (30 mL) in dry THF (100 mL) cooled at 5° C. and under nitrogen was added dropwise and at this temperature a solution of compound prepared above (26.8 g, 78 mmol) in dry THF (75 mL). After stirring 1 hour at 5° C. and then 1 hour at room temperature, the mixture was cooled at 10° C. and treated dropwise with 2N NaOH, to effect hydrolysis of the intermediate complex. The organic phase was separated and the solvent in vacuo evaporated. The residue was solved in ethyl ether, the solution washed with water, dried over MgSO4, and evaporated to give the required alcohol (23.3 g, 98%) as a yellow oil; IR (film) 3500, 1597 cm-1.

2-Bromomethyl-1-(4-methylphenyl)sulfonyl-1H-indole

To a solution of triphenylphosphine (20.2 g, 77 mmol) in dry CH2 Cl2 (80 mL) was added dropwise a solution of bromine (11.9 g, 77 mmol) in dry CH2 Cl2 (40 mL). The stirring was continued for 1 hour and then a solution of compound prepared above (23.2 g, 77 mmol) in dry CH2 Cl2 (40 mL) was added dropwise. The resulting mixture was left stirring for 12 hours. After removing the solvent the residue was taken up in ethyl acetate and washed with water. The organic extract was dried over MgSO4 and the solvent evaporated in vacuo. The residue was chromatographed over silica gel using toluene as eluant to give a yellow oil (21.0 g, 75%); IR (film) 1600 cm-1, MS ((70 eV): m/z 363 (M+, 12.6), 129 (100).

To a stirred solution of KOt.Bu (5.1 g, 45 mmol) in dry THF (25 mL) cooled at -40° C. was added dropwise at this temperature a solution of N-(phenylmethylene) DL-alanine methyl ester (8.7 g, 45 mmol) in dry THF (40 mL under nitrogen. The mixture was stirred 1 hour at -40° C. and then was added dropwise maintaining the temperature of a solution of compound prepared above (16.5 g, 45 mmol) in dry THF (50 mL). After the addition was completed, the mixture was stirred 2 hours at -20° C., then allowed to warm to room temperature and left overnight. The solvent was evaporated in vacuo, given a resin, which on trituration with ethyl ether and water gave the required compound (16.5 g, 75%) as a white solid, mp 151°-154° C.

A suspension of compound prepared above (16.1 g, 34 mmol) in ethanol (100 mL) and 2N hydrochloric acid (20 mL) was stirred overnight. After removing the solvent in vacuo the residue was suspended in water (400 mL), made basic with Na2 CO3, extracted with ethyl ether, and dried over MgSO4. The solvent was evaporated, providing an oil. This was subjected to silica gel chromatography using ethyl acetate:toluene 8:92 (v/v) then methanol:toluene 1:99 (v/v) as eluants to give the required compound (9.9 g, 75%) as an oil; IR (film) 1735 cm-1.

To a stirred solution of compound prepared above (9.9 g, 25 mmol) in dry THF (100 mL) was added a solution of 2-adamantylchloroformate (6.4 g, 30 mmol) in dry THF (15 mL) followed by a solution of triethylamine (6.1 g, 56 mmol) in dry THF (15 mL dropwise. After 1 hour stirring, the reaction mixture was filtered and the solvent removed in vacuo. The residue was stirred with a mixture of light petroleum (100 mL) and ethyl ether (20 mL) to give the required compound as a colorless solid, which was removed by filtration (13.9 g, 96%), mp 119°-122° C.

To a stirred solution of compound prepared above (0.54 g, 0.95 mmol) in a mixture of 1,4-dioxan (10 mL) and water (2 mL) was added LiOH (11.5 mg, 4.8 mmol) and stirred 5 days. After removing the solvent in vacuo, the residue was suspended in water, acidified with 1M citric acid solution to pH 4.5, and extracted with ethyl acetate. The organic phase was dried over MgSO4 and evaporated in vacuo to yield the acid (0.5 g, 96%) as nearly colorless foam, mp (noncrystalline) 106° C. (sintering).

A mixture of compound prepared above (0.48 g, 0.88 mmol) and 1,1'-carbonyldiimidazole (0.14 g, 0.88 mmol) in dry THF (10 mL) was stirred for 1 hour. To this mixture was then added dropwise a solution of 2-phenylethylamine (0.11 g, 0.90 mmol) in dry THF (5 mL). After stirring for 4 hours the solvent was removed in vacuo and the residue partitioned between water (25 mL) and CH2 Cl2 (50 mL). The organic phase was dried over MgSO4 and the solvent evaporated. The residue was chromatographed over silica gel using methanol:toluene 1:99 (v/v) as eluant to yield the title compound as a white solid, crystallized from 2-propanol (0.25 g, 43%), mp 166°-168° C.

A mixture of racemic N-[(2-adamantyloxy)carbonyl]2-methyl-3-[[1-(4-methylphenyl)sulfonyl]-1H-in dol-2-yl]alanine methyl ester (Step 6 of Example 45) (6.8 g, 12 mmol) and KOH (2.7 g, 48 mmol) in ethanol (100 mL) was stirred for 60 hours at 70° C. After removing the solvent in vacuo, the residue was partitioned between water (150 mL) and ethyl ether. The clear water phase was separated and acidified to pH 4.5 when an oil precipitated out, which slowly solidified. The solid was collected by filtration, washed successively with water, and dried to give the desired carboxylic acid (3.9 g, 81%) as a white solid, mp 210°-216° C.

A mixture of the compound prepared above (0.53 g, 1.3 mmol) and 1,1'-carbonyldiimidazole (0.22 g, 1.3 mmol) in dry THF (8 mL) was stirred for 1 hour. To this mixture was then added dropwise a solution of 2-phenethylamine (0.17 g, 1.4 mmol) in dry THF (4 mL). After stirring overnight, the solvent was evaporated in vacuo. The residue was solved in ethyl ether, washed with water, dried over MgSO4, and the solvent evaporated to leave a colorless foam which was crystallized from diisopropylether to yield the title compound (0.42 g, 64%), mp 168°-169° C.

A solution of benzyl ester of Example 93a (0.15 g, 0.2 mmol) in absolute ethanol (10 mL) was treated with 20% Pd(OH)2 on carbon (0.06 g) and placed under an atmosphere of hydrogen (50 bar) at 25° C. for 15 hours. The reaction mixture was then filtered and the filtrate concentrated in vacuo. The residue was chromatographed over silica gel using 2%-10% methanol: 98%-90% dichloromethane as eluant to yield the title compound (0.065 g, 50%) as an amorphous solid, mp 180°-187° C.

A solution of N-[(2-adamantyloxy)carbonyl]-2-methyl-3-(1H-indol-2-yl)-alanine (3.1 g, 8.4 mmol) and 1,1'-carbonyldiimidazole (1.4 g, 8.6 mmol) in dry THF (25 mL) was stirred for 2 hours. To this mixture was added the amine 15 (Scheme XII) in portions. After the addition was completed the resultant mixture was stirred 6 hours at 50° C., then allowed to cool to room temperature and left overnight. After removing the solvent in vacuo the residue was partitioned between water (50 mL) and ether (100 mL). The organic phase was separated, washed, dried over MgSO4, and the solvent evaporated. The residue was chromatographed over silica gel using MeOH:Ch2 Cl2 0.5-0.75:99.6-99.25 (v/v) as eluant. The required compound (3.3 g, 61%) was obtained as a colorless resin (mixture of isomers).

Step 2

A solution of the compound prepared above (3.3 g, 5.1 mmol) in absolute ethanol (30 mL) was treated with 20% Pd(OH)2 on carbon (0.75 g) and put under an atmosphere of hydrogen (50bar) at 30° C. with agitation for 15 hours. The reaction mixture was then filtered and the filtrate concentrated in vacuo. The residue was partitioned between water (40 mL) and ethyl acetate (70 mL). The organic phase was separated, washed, dried over MgSO4, and the solvent evaporated in vacuo to give the desired compound (2.6 g, 99%) as a colorless amorphous solid and a mixture of two diastereoisomers, mp 96°-102° C.

A solution of benzyl-hemisuccinate (1.1 g, 5.0 mmol) and 1,1'-carbonyldiimidazole (0.8 g, 5.0 mmol) in dry THF (10 mL) was stirred for 1 hour. To this mixture was added dropwise a solution of the amine of Example 95 (2.5 g, 4.9 mmol) in dry THF (10 mL) and the resultant mixture was stirred 4 hours at 50°-55° C., then cooled to room temperature and left overnight. After removing the solvent in vacuo, the residue was partitioned between water (50 mL) and CH2 Cl2 (100 mL). The organic phase was separated, washed, dried over MgSO4, and the solvent evaporated in vacuo. The residue was chromatographed over silica gel using MeOH:CH2 Cl2 0.5-1.99:5-99 (v/v).